Patient-specific knee alignment guide and associated method

ABSTRACT

A method of preparing a knee joint for a prosthesis in a patient includes mating a patient-specific three-dimensional curved inner surface of a femoral alignment guide onto a corresponding three-dimensional femoral joint surface of the patient. The patient-specific three-dimensional curved inner surface is preoperatively configured from medical scans of the knee joint of the patient. First and second holes are drilled into an anterior portion of the femoral joint surface through corresponding first and second guiding apertures of the femoral alignment guide.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is continuation-in-part of U.S. patent application Ser.No. 13/800,334 filed on Mar. 13, 2013, which is a divisional of U.S.patent application Ser. No. 13/303,546 filed on Nov. 23, 2011, now U.S.Pat. No. 8,398,646 issued on Mar. 19, 2013, which is a continuation ofU.S. patent application Ser. No. 11/756,057 filed on May 31, 2007, whichis now U.S. Pat. No. 8,092,465 issued on Jan. 10, 2012, which claims thebenefit of U.S. Provisional Application No. 60/812,694 filed on Jun. 9,2006. The disclosures of the above applications are incorporated hereinby reference.

INTRODUCTION

Proper alignment of prosthetic components in knee arthroscopy is animportant factor in the longevity and function of the implant.Misalignment can cause increased wear of the implant, patientdiscomfort, and functional limitation.

Although various methods and devices are known for addressing the aboveproblems, patient specific alignment methods and alignment guides arestill desirable.

SUMMARY

The present teachings provide a method of preparing a joint for aprosthesis in a patient. In one aspect, the method includes obtainingscan data associated with the joint of the patient, preparing athree-dimensional image of the joint based on the scan data, preparingan interactive initial surgical plan based on the scan data, sending thesurgical plan to a surgeon, receiving a finalized surgical plan fromsurgeon, and preparing an image of a patient-specific alignment guide.

In another aspect, the method includes securing a patient-specificalignment guide to a joint surface of the patient, attaching a guideelement through the alignment guide to the joint surface, removing thealignment guide without removing the guide element, and resecting thejoint surface using the guide element.

The present teachings also provide a method of preparing a knee jointfor a prosthesis in a patient. The method includes locking apatient-specific femoral alignment guide onto a femoral joint surface ofthe patient, inserting at least one first guide element through thefemoral alignment guide into the anterior or the anterior-medial side ofthe femoral joint surface, and drilling resection-locating apertures inthe distal side of femoral joint surface. The method further includesremoving the femoral alignment guide without removing the first guideelement, supporting a femoral resection device on the first guideelement, and resecting the femoral joint surface.

The present teachings further provide an orthopedic device for preparinga knee joint for a prosthesis in a patient. The orthopedic deviceincludes a femoral alignment guide having a patient-specificthree-dimensional curved inner surface. The curved inner surface ispreoperatively configured from medical image scans of the knee joint ofthe patient to nestingly conform and mate and match only in one positionto a corresponding three-dimensional femoral surface of a joint surfaceof the patient. The femoral alignment guide has a first guiding aperturecorresponding to a distal portion of the femoral surface and a secondguiding aperture corresponding to an anterior portion of the femoralsurface.

According to various embodiments, a method of preparing a knee joint fora prosthesis in a patient is disclosed. The method includes mating apatient-specific three-dimensional curved inner surface of a femoralalignment guide onto a corresponding three-dimensional femoral jointsurface of the patient, the patient-specific three-dimensional curvedinner surface preoperatively configured from medical scans of the kneejoint of the patient, drilling a first hole into an anterior portion ofthe femoral joint surface through a corresponding first guiding apertureof the femoral alignment guide and drilling a second hole into ananterior portion of the femoral joint surface through a correspondingsecond guiding aperture of the femoral alignment guide. In the method,the second guiding aperture is asymmetrically located relative to thefirst guiding aperture on the femoral alignment guide. The method canfurther include mating a portion of the inner surface of the femoralalignment guide to articular cartilage covering the femoral jointsurface. The method can further include mating a portion of the innersurface of the femoral alignment guide to a bone portion underlyingarticular cartilage of the femoral joint surface. The method can furtherinclude inserting first and second guiding pins through thecorresponding first and second guiding apertures and first and secondholes. The method can further include removing the femoral alignmentguide without removing the first and second guiding pins. The method canfurther include sliding the femoral alignment guide through openportions of corresponding perimeters of the first and second guidingapertures. The method can further include supporting a cutting block onthe first and second guiding pins. The method can further includeguiding a patient-specific femoral resection through the cutting block,the patient-specific resection determined by preoperative configuringthe first and second guiding apertures on the femoral alignment guide tocorrespond to the patient-specific resection.

According to various embodiments, a method of preparing a knee joint fora prosthesis in a patient may include mating a patient-specificthree-dimensional curved inner surface of a femoral alignment guide ontoa corresponding three-dimensional femoral joint surface of a patient,the patient-specific three-dimensional curved inner surfacepreoperatively configured from medical scans of the knee joint of thepatient, drilling first and second holes into an anterior portion of thefemoral joint surface through corresponding first and second guidingapertures of the femoral alignment guide, wherein the first and secondguiding apertures are preoperative configured for locating a femoralresection of the patient according to the medical scans of the patientand a preoperative surgical plan for the patient, and inserting firstand second guiding pins through the corresponding first and secondguiding apertures and the first and second holes. The method may furtherinclude removing the femoral alignment guide without removing the firstand second guiding pins. The method may further include sliding thefemoral alignment guide through open portions of correspondingperimeters of the first and second guiding apertures. The method mayfurther include supporting a cutting block on the first and secondguiding pins. The method may further include guiding a patient-specificfemoral resection through the cutting block. The method may furtherinclude mating a portion of the inner surface of the femoral alignmentguide to at least one of articular cartilage and underlying bone of thefemoral joint surface.

According to various embodiments, a method of preparing a knee joint fora prosthesis in a patient can include mating a patient-specificthree-dimensional curved inner surface of a tibial alignment guide ontoa corresponding three-dimensional tibial joint surface of the patient,the patient-specific three-dimensional curved inner surfacepreoperatively configured from medical scans of the knee joint of thepatient, and wrapping a portion of the tibial alignment guide around ananterior-medial edge of the tibial joint surface. The method may furtherinclude drilling a first tibial guiding hole into an anterior portion ofthe tibial joint surface through a first corresponding anterior apertureof the tibial alignment guide. The method may further include drilling asecond tibial guiding hole into an anterior portion of the tibial jointsurface through a second corresponding anterior aperture of the tibialalignment guide. The method may further include inserting first andsecond guiding pins through the corresponding first and second anteriorapertures and into the corresponding first and second tibial guidingholes. The method may further include removing the tibial alignmentguide without removing the first and second guiding pins by sliding thetibial alignment guide through open portions of corresponding perimetersof the first and second anterior apertures of the tibial alignmentguide.

Further areas of applicability of the present invention will becomeapparent from the description provided hereinafter. It should beunderstood that the description and specific examples are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a flowchart of an exemplary method of preparing patientspecific alignment guides according to the present teachings;

FIG. 2 is a flowchart of an alignment method according to the presentteachings;

FIG. 3 is a view illustrating the mechanical axis in a patient'sanatomic image;

FIG. 4 is a view illustrating the transepicondylar and cylindrical axesin a patient's anatomic image;

FIG. 5 is a view illustrating the mechanical and anatomic axes in apatient's femoral image;

FIG. 6 is a flowchart of an exemplary method of using patient specificalignment guides according to the present teachings;

FIG. 7 is an exemplary image of a patient's anatomy with implants shown,as viewed in interactive software according to the present teachings;

FIG. 8 is a perspective view of an exemplary femoral alignment guideaccording to the present teachings, shown next to a correspondinganatomic femur;

FIGS. 9A and 9B are perspective views of the femoral alignment guide ofFIG. 8 shown mounted on the femur;

FIGS. 10A and 10B are perspective views of the femoral alignment guideof FIG. 8 shown with spring pins securing the alignment guide to thefemur;

FIG. 11A is a perspective view of the femoral alignment guide of FIG. 8shown with a drill guide;

FIG. 11B is a perspective view of the femoral alignment guide of FIG.11A shown with two guide pins drilled through the drill guide;

FIG. 11C is perspective view of the femoral alignment guide of FIG. 11Bshowing the removal of the drill guide;

FIG. 12A is a perspective view of the femoral alignment guide of FIG.11C shown after the removal of the drill guide;

FIG. 12B is a perspective view of the femoral alignment guide of FIG.12A shown after the removal of the spring pins;

FIG. 13A is a perspective view of FIG. 12B illustrating the guide pinsafter the removal of the femoral alignment guide;

FIG. 13B illustrates a detail of the femoral alignment guide of FIG.12B;

FIG. 14A is a perspective view of a distal femoral cutting block shownover two pins on a patient's femur, according to the present teachings;

FIG. 14B is a perspective view of a distal femoral cutting block shownover two guide pins on a patient's femur, according to the presentteachings;

FIG. 15A is a perspective view of an exemplary 4-in-1 cutting blockpositioned on the femur with reference to holes corresponding to thespring pins;

FIG. 15B a perspective view of the cutting block of FIG. 15A shown witha cutting blade;

FIG. 16A is a perspective view of a tibial alignment guide according tothe present teachings, shown mounted on the tibia;

FIG. 16B is a perspective view of the tibial alignment guide of FIG. 16Ashown with a drill guide;

FIG. 16C is a perspective view of FIG. 16B illustrating the guide pinsafter the removal of the tibial alignment guide;

FIG. 16D is a perspective view of FIG. 16C illustrating a tibial cuttingguide mounted on the guide pins;

FIG. 17 is a perspective environmental view of a distal femur with aguide positioned thereon and an instrument forming a bore in the femur;

FIG. 17A is a perspective view of the guide of FIG. 17; and

FIG. 18 is an environmental view of a distal femur with a guidepositioned thereon and an instrument position in a bore through theguide.

DESCRIPTION OF VARIOUS ASPECTS

The following description is merely exemplary in nature and is in no wayintended to limit the scope of the present teachings, applications, oruses. For example, although the present teachings are illustrated foralignment guides in knee surgery, the present teachings can be used forother guides, templates, jigs, drills, rasps or other instruments usedin various orthopedic procedures.

The present teachings provide a method for preparing patient-specificalignment guides for use in orthopedic surgery for a joint, such as, forexample, the knee joint. Conventional, not patient-specific, prosthesiscomponents available in different sizes can be used with the alignmentguides, although patient-specific femoral and tibial prosthesiscomponents prepared with computer-assisted image methods can also beused. Computer modeling for obtaining three dimensional images of thepatient's anatomy, such as a patient's joint, for example, thepatient-specific prosthesis components, when used, and the alignmentguides and templates can be provided by various CAD programs and/orsoftware available from various vendors or developers, such as, forexample, from Materialise USA, Ann Arbor, Mich.

Referring to FIG. 1, an MRI scan or a series of CT scans of the entireleg of the joint to be reconstructed, including hip and ankle, as shownin FIG. 3, can be performed at a medical facility or doctor's office, ataspect 10. In some cases, the scan may be performed with the patientwearing an unloader brace to stress the ligaments. The scan dataobtained can be sent to a manufacturer, at aspect 20. The scan data canbe used to construct a three-dimensional image of the joint and providean initial implant fitting and alignment in a computer file form orother computer representation. The initial implant fitting and alignmentcan be obtained using an alignment method, such as the alignment methodillustrated in FIG. 2 and described below. Other alignment methods canalso be used, such as alignment protocols used by individual surgeons.

The outcome of the initial fitting is an initial surgical plan that canbe printed or provided in electronic form with corresponding viewingsoftware. The initial surgical plan can be surgeon-specific, when usingsurgeon-specific alignment protocols. The initial surgical plan, in acomputer file form associated with interactive software, can be sent tothe surgeon, or other medical practitioner, for review, at 30. Thesurgeon can incrementally manipulate the position of images of implantcomponents 502, 504 in an interactive image form 500 of the joint, asillustrated in FIG. 7. After the surgeon modifies and/or approves thesurgical plan, the surgeon can send the final, approved plan to themanufacturer, at 40.

Various methods of sending the initial and final surgeon-approvedsurgical plans can be used. The surgical plans can be, for example,transferred to an electronic storage medium, such as CD, DVD, flashmemory, which can then be mailed using regular posting methods.Alternatively, the surgical plan can be e-mailed in electronic form ortransmitted through the internet or other web-based service, without theuse of a storage medium.

After the surgical plan is approved by the surgeon, patient-specificalignment guides for the femur and tibia can be developed using a CADprogram or other imaging software, such as the software provided byMaterialise, for example, according to the surgical plan, at 50.Computer instructions of tool paths for machining the patient-specificalignment guides can be generated and stored in a tool path data file,at 60. The tool path can be provided as input to a CNC mill or otherautomated machining system, and the alignment guides can be machinedfrom polymer, ceramic, metal or other suitable material, and sterilized,at 70. The sterilized alignment guides can be shipped to the surgeon ormedical facility, at aspect 79 for use during the surgical procedure.

Referring to FIG. 2, an exemplary method for providing the initialimplant fitting and alignment is illustrated. The method can be modifiedor completely replaced according to a surgeon-specific alignmentprotocol. After the scan data is converted to three dimensional imagesof the patient anatomy from hip to ankle, images of the tibial andfemoral components can be manipulated for obtaining patient-specificalignment by making use of the femoral and tibial mechanical axes 402,404, illustrated in FIG. 3, and the transepicondylar and cylindricalaxes 406, 408, illustrated in FIG. 4. Images of the knee joint anatomycan include images of the joint surfaces of the distal femur andproximal tibial with or without the associated soft tissues, such asarticular cartilage, on the respective bone surfaces.

Generally, the femoral mechanical axis is defined as the line joiningthe center of the femoral head and the center of the intercondylarnotch. The femoral anatomic axis is defined as the line along the centerof the femoral shaft. The tibial mechanical axis is the line joining thecenter of the tibial plateau to the center of the tibial plafond or thecenter of the distal end of the tibia. The tibial anatomic axis is theline along the center of the tibial shaft. The transepicondylar axis isthe line connecting the most prominent points of the epicondyles. Thecylindrical axis is the line connecting the centers of the condyles whenthe condyles are approximated by coaxial cylinders. A detaileddiscussion of the various joint-related axes and the relation of thetransepicondylar axis 406 and cylindrical axis 408 is provided inEckhoff et al, Three-Dimensional Mechanics, Kinematics, and Morphologyof the Knee Viewed in Virtual Reality, J Bone Joint Surg Am. 87:71-80,2005, which is incorporated herein by reference.

The relation of the femoral mechanical axis 402 to the anatomic axis 410for the femur is illustrated in FIG. 5. The femoral and tibialmechanical axes 402, 404 may or may not coincide, as illustrated in FIG.3. In the following discussion, reference is made to a single mechanicalaxis 401 encompassing the femoral and tibial mechanical axes 402, 404.The alignment procedure illustrated in FIG. 2 makes use of themechanical, anatomic, transepicondylar and cylindrical axes in variousdegrees. The present teachings, however, are not limited to thisalignment procedure. Multiple alignment procedures can be provided toaccommodate the experience and preference of individual surgeons. Forexample, the alignment procedure can be based on the anatomic andmechanical axes, or can be substantially based on the cylindrical axis.Further, the alignment procedure can be deformity-specific, such that isadapted, for example, to a valgus or varus deformity.

With continued reference to FIGS. 2-5 and 7, in the image space, thetibial component 504 can be aligned 90° to the mechanical axis 401, ataspect 90. In the frontal plane, the femoral component 502 can bealigned 90° to the mechanical axis 401, at aspect 100. The femoralcomponent 502 can be positioned for “x” mm distal resection, at 110,where “x” can be about 9 mm or as other measurement as indicated for aspecific patient. The femoral component 502 can be rotated until itsdistal surfaces are at 90° to the distal femoral bow (componentflexion/extension), at 120. The femoral component 502 can be movedanteriorly/posteriorly until the posterior medial condyle resection isgreater or equal to “x” mm, at aspect 130.

The femoral component size can be determined by observing the anteriorresection relative to anterior cortex, at 140. If the femoral size isadjusted, the new size can be positioned at the same location relativeto the distal and posterior cut planes.

The cylindrical axis 408 of the femur can be located, at aspect 150. Thetibia can be flexed 90° relative to the femur about the cylindrical axis408, at aspect 160. The femoral component 502 can be rotated about themedial condyle until a rectangular flexion space is achieved, at aspect170. Alternatively, the rotation can be relative to the transepicondylaraxis, anterior/posterior axis, and posterior condylar axis, or acombination of all four axes. The femoral component 502 can be centeredor lateralized on the femur, at aspect 180. The location for variousdistal holes for locating the femoral resection block can be alsodetermined.

Referring to FIGS. 6, and 8-15B, an exemplary alignment guide 600 andmethod of use is illustrated in connection with the patient's femur 80.Reference numbers 200-250 relate to aspects of the method of FIG. 6 andare described in connection with the instruments shown in FIGS. 8-15Bfor the femur 80.

The alignment guide 600 includes an inner guide surface 640 designed toclosely conform, mate and match the femoral joint surface 82 of thepatient in three-dimensional space such that the alignment guide 600 andthe femoral joint surface are in a nesting relationship to one another.Accordingly, the alignment guide 600 can conform, mate and snap on or“lock” onto the distal surface of the femur 80 in a unique positiondetermined in the final surgical plan, at 200. The alignment guide 600can have variable thickness. In general, the alignment guide 600 can bemade as thin as possible while maintaining structural stiffness. Forexample, certain areas around and adjacent various securing or guidingapertures 602, 606 can be thickened to provide structural support forguiding a drill or for holding a drill guide or supporting other toolsor devices. Exemplary thickened areas 642 are indicated with dottedlines in FIGS. 9A and 9B. Other areas can be cut out for viewing theunderlying bone or cartilage of femoral joint surface 82. Viewing areas644 are indicated with dotted lines in FIGS. 9A and 9B.

Referring to FIGS. 10A and 10B, the alignment guide 600 can be securedto the femoral joint surface 82 with fixation members or fasteners 624,such as, for example, spring pins, or other securing fasteners that arereceived through distal apertures 602 of the alignment guide 600.Locating holes 602 a corresponding to the apertures 602 of the alignmentguide 600 can be drilled in the distal femur 80 to locate a femoralresection block or other cutting device 620, such as a 4-in-1 cuttingblock, at 220. The alignment guide 600 can also include guidingapertures 606. Guiding apertures 606 are shown in the anterior-medialside relative to the femur 80, but can also be made in the anterior sideof the femur 80 or in other locations and orientations. The guidingapertures 606 can be counter-bored and have a partially open portion 608in their perimeter for sliding the alignment guide off pins or otherfasteners without removing such fasteners, as shown in FIG. 13A anddiscussed below.

Referring to FIGS. 11A and 11B, a drill guide 700 can be placed inalignment with the guiding apertures 606. The drill guide 700 caninclude a body 702 having guiding bores 704 corresponding to the guidingapertures 606. The guiding bores 704 can have portions 706 that extendbeyond the body 702 and into the guiding apertures 606 for facilitatingalignment. The drill guide 700 can also include a handle 710 extendingsideways from the body 702 and clear from the drilling path.

Referring to FIG. 11C, guide elements 604, such as pins or otherfasteners, for example, can be drilled through the guiding bores 704 ofthe drill guide 700 on the anterior or anterior-medial side of the femur80, at aspect 210 of the method of FIG. 6. The guide elements 604 can beparallel or at other angles relative to another. The guide elements 604can define a plane that is parallel to a distal resection plane for thefemur.

Referring to FIG. 12A, the drill guide 700 can be removed. Referring toFIGS. 12B-13B, the fasteners 624 can be removed, and the alignment guide600 can be removed from the femur 80 by sliding the alignment guide 600off the guide elements 604 through the open portions 608 of the guidingapertures 606 without removing the guide elements 604 at theanterior/medial corner of the knee, at aspect 230 of FIG. 6.

The guide elements 604 can be used to prepare the joint surfaces for theprosthesis by mounting cutting guides/blocks for resecting the jointsurface. Alternatively, a robotic arm or other automated, guided orcomputer controlled device that can guide the resections based on thepre-operative surgical plan can be mounted on the guide elements 604 andassist the surgeon in preparing the joint surface for the prosthesis.

Referring to FIGS. 14A and 14B, exemplary distal cutting blocks 610 a,610 b that can be mounted over the guide element 604 for making thedistal resection, at aspect 640 of FIG. 6, are illustrated. A thirdfixation element 605, obliquely oriented relative to the guide elements604 can also be used. The distal cutting blocks 610 a, 610 b can have aninner surface 612 a, 612 b that generally follows the shape of the femur80 to a lesser or greater degree. The distal cutting blocks 610 a, 610 bcan be disposable or re-usable.

Referring to FIGS. 15A and 15B, after the distal resections are madewith the distal cutting block 610 a or 610 b, the femoral resectionblock 620 can be mounted with pegs or other supporting elements 622 intothe holes 602 a corresponding to the fasteners 624. The femoralresections can be made using, for example, a cutting blade 630 throughslots 632 of the femoral resection block 620, at aspect 250 of FIG. 6.

Referring to FIGS. 6 and 16A-D, an exemplary alignment guide 600 isillustrated in connection with the patient's tibia 81. Reference numbers260-300 relate to aspects of the method of FIG. 6 and are described inconnection with the instruments shown in FIGS. 16A-16D for the tibia.

The alignment guide 600 can conform, nestingly mate in three-dimensionalspace and snap on or “lock” by design onto the tibia 81 in a uniqueposition, at aspect 260 of FIG. 6. The alignment guide 600 can wraparound the anterior-medial edge of the tibia 81, as shown in FIG. 16A.The drill guide 700 can be aligned with the counter-bored guidingapertures 606 of the alignment guide 600, as shown in FIG. 16B. Two ormore guide elements 604 can be placed on the anterior medial side of thetibia, at aspect 270 of FIG. 6. An additional fixation element can alsobe used for additional securing for the alignment guide 600. The drillguide 700 and the alignment guide 600 can be removed, leaving behind theguide elements 604 attached, at aspect 280 of FIG. 6, and as shown inFIG. 16C. A disposable or reusable tibial cutting block 750 can be slidover the guide elements 604, at aspect 290 of FIG. 6, and as shown inFIG. 16D. The tibial cutting block 750 can include a series of holes752, allowing the cutting block 750 to be translated proximally ordistally to adjust the level of the distal resection. The tibialresection can be made, at 300.

The present teachings provide patient-specific alignment guides that canbe used for alignment in orthopedic surgery. Each alignment guideincludes an inner surface that nestingly mates and conforms inthree-dimensional space with a corresponding joint surface of a specificpatient. The alignment guides can be used for locating guide elements onthe joint surface. After the alignment guides are removed, cuttingguides or other cutting devices, including automated or robotic devices,can be mounted on the guide elements for making various resection cuts.Because the alignment guides are not used for cutting, the alignmentguides do not require substantive thickness to extend anteriorly, andconsequently have a lower profile, and less weight. Additionally,because the alignment guides are removed before cutting, the presentteachings provide increased ability to visualize the cuts and thecutting process.

Subchondral Access

According to various embodiments, the guide 600 or any appropriate guidemember, including the guide 600′ illustrated in FIG. 17, can bepositioned relative to a bone, such as the femur 80, for performing aprocedure relative to the bone. For example, as illustrated in FIG. 17,the guide 600′ can be positioned relative to the femur 80 to guide adrilling member, such as a drill bit or pin 820, to obtain access to aninterior portion of the femur 80 that is beneath a surface of the femur.Once access is obtained to a portion of the femur, such as below thesurface of a femur, a procedure can be performed on the femur forvarious purposes. For example, the procedure can include a tumorresection, a bone filling, and/or a bone replacement.

According to various procedures, a portion of bone that is beneath acondyle, also referred to as subchondral, can be repaired or replacedwith a bone void filling material, such as in a procedure generallydisclosed using Subchondroplasty® instruments and/or access devices thatare provided by Knee Creations LLC, having a place of business inWestchester, Pa., USA and/or Subchondroplasty Orthopedics LLC having aplace of business in Westchester, Pa., USA. The Subchondroplasty®instruments are known to assist in obtaining access to an area of a bonethat is beneath a condyle to perform a procedure interior to the bone toassist in maintaining the condyle region, including a condylarcartilage. For example, a subchondular bone can be reinforced orstrengthened with a selected material to strengthen the bone and toreinforce and strengthen support of the condylar cartilage. Appropriatematerials can be biomimetic bone substitute material that can be used tostrengthen and/or cause replacement of subchondular bone.

Regions that may need to be strengthened include bone marrow lesionsthat form and may weaken support of the condylar cartilage. Accordingly,the appropriate bone substitute materials can be placed in or around thebone marrow lesions to cause regeneration of the bone and strengtheningthereof. Appropriate bone substitute materials can include Accufill®bone void filler that includes injectable calcium phosphate, provided byKnee Creations, LLC having a place of business in New York, N.Y., USA.According to various embodiments, bone void filler materials, includingcalcium phosphate, can be placed in a bone defect to cause regrowthand/or remineralization of a selected bone region.

It is also understood that the guide 600 can be used to place aninstrument, such as the guide elements 604, through one or more guidingapertures 606 to position the instrument at an appropriate and selectedlocation within the bone. For example, as discussed above, the guide 600can be designed to include the inner guide surface 640 that closelyconforms or matches a femoral joint surface 82. The inner guide surface640 is generally or specifically a three-dimensional curved innersurface that is preoperatively configured from medical image scans ofthe patient, such as a knee joint of the patient, to nestingly conformand mate and match only in one position to a correspondingthree-dimensional femoral surface of the patient. The guiding apertures606, therefore, are positioned at a selected, known, and specificlocation relative to the femur 80. The design of the inner guide surface640 and the placement of the guiding aperture 606 may assist in aguiding and insuring guiding of any appropriate instrument relative toan interior portion of the bone, including the femur 80. The apertures606′ can define a patient specific axis, as discussed herein, to guidean instrument to form a patient specific hole or bore and to a patientspecific location. Thus, any appropriate procedure can be performed atan interior of the bone. Appropriate procedures can further includeremoving a tumor within the bone, removing necrotic tissue within thebone, positioning a bone-growing implant, positioning a supportingdevice within the bone, or other appropriate procedure.

It is understood that the guide 600, or any appropriate guide, can bedesigned to mate with a surface of any appropriate bone portionincluding a distal femoral bone portion surface, a distal anteriorfemoral bone surface, a vertebral bone surface, a proximal tibial bonesurface, or any other appropriate bone surface. Further, a procedure canbe performed with the guide 600, according to various embodiments toassist in fixation of bone, implanting an implant transverse through afracture, tumor removal, bone surface supporting implant or device, orother appropriate procedure.

With reference to FIG. 1, scan data can be generated or obtained ataspect 10. The scan data can include various image data of a patientincluding MRI scan data and CT scan data. The scan data can be used togenerate an initial surgical plan at aspect 30 which is finalized ataspect 40 to design patient-specific guides at aspect 50. The patientspecific guides are then made, including being machined, at aspect 70and are then shipped to a surgeon at aspect 79. The plan that isfinalized by the surgeon at aspect 40 can be based upon variousdiagnoses of a patient. For example, a diagnosis of a bone loss, tumor,fracture, and the like can be made based upon the scan data of thepatient. The finalized plan can include placement and/or orientation ofa guiding aperture 606′ in the guide 600′ such that instruments areguided to selected and known diagnosed regions of the patient. It willbe understood that although the following discussion relates generallyto a subchondrol weakening or lesion relative to a distal femur in aknee joint, any diagnosis can be made and that the guide 600′ can bedesigned, according to method illustrated in FIG. 1, to allow forpositioning of an instrument relative to the diagnosed region.

Turning reference to FIGS. 17 and 17A, the femur 80 is schematicallyillustrated. The femur 80 can be illustrated as image data on a displaydevice, such as a computer display device. The FIG. 17 illustrating thefemur 80 can represent a natural femur and/or image data or a conversionof image data into a three-dimensional display for viewing by a userand/or operator, including a surgeon. The femur 80 can include thecondylar cartilage 800 that can extend over at least a portion of thefemur 80 including a condylar region 802 that can define at least aportion of the femoral joint surface 82. Other portions of the femur 80may not include cartilage, such as medial and/or anterior regions of thefemur 80. As illustrated and discussed above, the femoral joint surface82 can form at least a portion of the knee joint where the femur canarticulate with a proximal portion of the tibia 81. Near the condyle 82and generally below the condylar cartilage 800, a bone lesion and/orweakened bone region 806 can be viewed (i.e. seen in the scan data ofthe patient) and/or diagnosed. The weakened bone region 806 can bediagnosed or viewed based upon generally known techniques, includingviewing the scans, e.g. MRI and CT scans, of the patient and/or aconversion or reconstruction of the scanned data by one skilled in theart. It will be understood that the weakened bone region 806 can berepresentative of any appropriate diagnosis, including diagnosis of atumor, fracture, bone marrow lesions, or other bone defect or area forperforming a procedure.

Once the weakened bone region 806 is diagnosed in the femur 800, themethod illustrated in FIG. 1 can be used to design a patient-specificguide at aspect 50, machine and sterilize the patient-specific guide ataspect 70, and ship the guide to the surgeon at aspect 79. Thepatient-specific guide 600′ can include an inner patient specificsurface 640′ to contact a selected portion of a surface of the femur 80.It is understood that the guide 600′ can be designed to contact amedial, lateral, anterior, anterior medial, anterior lateral, or anyappropriate portion of the bone. The patient specific guide 600′ and theinner surface 640′ can be similar to the guide 600 and inner surface 640discussed above in that the guide can contact, nest, and/or lock to aspecific portion of the anatomy to align the patient specific guidingaperture 606′ relative to a specific region, such as the weakened region806.

As exemplarily illustrated in FIG. 17, an anterior-medial positioning ofa patient-specific guide 600′ is illustrated. The guide 600′ may includeone or more of the guide apertures 606′ that can be formed through theguide 600′. An instrument, including the guide member 604, the drill820, or other appropriate member can be positioned through the aperture606′ to form a portal or bore 870 into the femur 80. The bore 870 may bea blind bore that terminates away from the cartilage 800 such that aport or hole is not formed into or through the cartilage 800. Thus, thebore 870 will generally extend only through the bone material and thebore forming instrument need not contact or engage the cartilage 800.

The drill bit 820 can be passed through the guide 600′, such as throughthe guide aperture 606′, to engage the femur 800 and drill to theweakened bone region 806. The positioning of the guide 600′ and theguiding aperture 606′ can be such that the drill 820 will proceed alonga patient specific axis 822 through the femur 800 and to the weakenedbone region 806. Based upon the scan data from aspect 10 of FIG. 1 andthe plan at aspect 40 a patient specific mark can also be placed on thedrill bit 820, including a visible demarcation 830, such that thesurgeon knows when the drill bit 820, including a tip 832, has moved anappropriate amount into the femur 80. The appropriate amount can includethe tip 832 being positioned at the weakened bone region 806. Thesurgeon may then stop progressing the drill 820 into the femur 80 andperform a procedure through the bore 870 at a patient specific depth.

Once the drill bit 820 has been positioned such that at least the tip832 has reached the weakened bond region 806, a procedure can occurrelative to the femur 80 and the weakened bone region 806. According tovarious embodiments, a material may be delivered to the weakened boneregion 806, such as a bone void filling material, other pharmaceutical,steroid, demineralized bone, or other appropriate material. According tovarious embodiments, the drill bit 820 can be cannulated such that amaterial can be delivered through the drill bit 820 directly to theweakened bone region 806. According to various embodiments, however, thedrill bit 820 can be removed and a syringe 860 can be moved relative tothe femur 80.

With reference to FIG. 18, the syringe 860 can be positioned relative tothe femur 80 such that at least a needle or cannulated member 862 ispositioned through the bore 870 that is formed within the femur 80 bythe drill bit 820. The bore 870 remains in the femur 80 after the drillbit 820 is withdrawn. The bore 870 is generally a blind bore such thatit terminates beneath an external surface of the femur 80. Accordingly,the blind bore 870 does not extend to a surface of the cartilage 800 nordoes the drill bit 820 penetrate or contact the cartilage 800. Thus, thecannulated member 862 of the syringe 860 will also not penetrate orcontact cartilage 800 during a selected procedure. The bore 870 may alsooriginate at a cartilage free region of the femur 80, or any appropriatebone. A barrel or reservoir 880 can be filled with the selected materialthat can be ejected through the cannulated member 862 by a plungermechanism or other pump mechanism 882. A selected treatment, such as abone void filling material can then be injected into the bone region 806from the syringe 860.

It is understood, however, that other instruments can be passed throughthe bore 870 to the weakened bone region 806. Again, the weakened boneregion 806 may represent any bone or anatomical feature for which aprocedure is appropriate. For example, as discussed above, the weakenedbone region 806 can relate to a tumor within the bone, such as withinthe femur 80. Accordingly, an excising instrument may pass through thebore 870 to the weakened bone region 806 and a biopsy, excision, orother procedure can occur. For example, a biopsy can be obtained of thematerial within the weakened bone region 806 for a further diagnosis,such as confirmation of a cancerous growth or other growth.

Regardless of the diagnosis of the patient, including the weakened boneregion 806, the guide 600′ can be designed based upon the plan asillustrated in FIG. 1 to include the guide aperture 606′ to guide aninstrument relative to a diagnosed region, including the weakened boneregion 806. The guiding aperture 606′ can allow for guiding an accessforming instrument, such as the drill bit 820, and/or a treatmentinstrument, such as the syringe 860 or a biopsy instrument, as discussedabove. The guide 600′ can be positioned relative to the femur 80 forvarious and multiple portions of a procedure to obtain access to asingle region for both accessing and/or treating the single region.

The diagnosis region, including the weakened bone region 806 illustratedin FIG. 17, can be accessed due to the patient-specific orientation ofthe guiding aperture 606′ and/or the inner surface 640′ of the guide600′ that contacts the femur 80. Accordingly, a procedure can occur thatis subchondral and does not engage, contact, or pierce the cartilage 800of the femur 80. It is understood, in a similar manner, that the guide600′ can be designed to contact any specific bone portion for engaging,treating, or accessing a portion of the bone that is adjacent or near acartilage or soft tissue portion without contacting or piercing the softtissue or cartilage portion. Thus, a procedure and/or treatment of thepatient can be performed without disturbing the soft tissue, includingcartilage, adjacent or on a bone of a patient.

The foregoing discussion discloses and describes merely exemplaryarrangements of the present teachings. One skilled in the art willreadily recognize from such discussion, and from the accompanyingdrawings, that various changes, modifications and variations can be madetherein without departing from the spirit and scope of the presentteachings.

1. (canceled)
 2. A method of preparing a knee joint for a prosthesis ina patient, the method comprising: mating a patient-specificthree-dimensional curved inner surface of a femoral alignment guide ontoa corresponding three-dimensional femoral joint surface of the patient,the patient-specific three-dimensional curved inner surfacepreoperatively configured from medical scans of the knee joint of thepatient; drilling a first hole into an anterior portion of the femoraljoint surface through a corresponding first guiding aperture of thefemoral alignment guide; and drilling a second hole into an anteriorportion of the femoral joint surface through a corresponding secondguiding aperture of the femoral alignment guide.
 3. The method of claim2, wherein the second guiding aperture is asymmetrically locatedrelative to the first guiding aperture on the femoral alignment guide.4. The method of claim 2, further comprising mating a portion of theinner surface of the femoral alignment guide to articular cartilagecovering the femoral joint surface.
 5. The method of claim 2, furthercomprising mating a portion of the inner surface of the femoralalignment guide to a bone portion underlying articular cartilage of thefemoral joint surface.
 6. The method of claim 2, further comprisinginserting first and second guiding pins through the corresponding firstand second guiding apertures and first and second holes.
 7. The methodof claim 6, further comprising removing the femoral alignment guidewithout removing the first and second guiding pins.
 8. The method ofclaim 7, further comprising sliding the femoral alignment guide throughopen portions of corresponding perimeters of the first and secondguiding apertures.
 9. The method of claim 8, further comprisingsupporting a cutting block on the first and second guiding pins.
 10. Themethod of claim 9, further comprising guiding a patient-specific femoralresection through the cutting block, the patient-specific resectiondetermined by preoperative configuring the first and second guidingapertures on the femoral alignment guide to correspond to thepatient-specific resection.
 11. A method of preparing a knee joint for aprosthesis in a patient, the method comprising: mating apatient-specific three-dimensional curved inner surface of a femoralalignment guide onto a corresponding three-dimensional femoral jointsurface of a patient, the patient-specific three-dimensional curvedinner surface preoperatively configured from medical scans of the kneejoint of the patient; drilling first and second holes into an anteriorportion of the femoral joint surface through corresponding first andsecond guiding apertures of the femoral alignment guide, wherein thefirst and second guiding apertures are preoperative configured forlocating a femoral resection of the patient according to the medicalscans of the patient and a preoperative surgical plan for the patient;and inserting first and second guiding pins through the correspondingfirst and second guiding apertures and the first and second holes. 12.The method of claim 11, further comprising removing the femoralalignment guide without removing the first and second guiding pins. 13.The method of claim 12, further comprising sliding the femoral alignmentguide through open portions of corresponding perimeters of the first andsecond guiding apertures.
 14. The method of claim 13, further comprisingsupporting a cutting block on the first and second guiding pins.
 15. Themethod of claim 14, further comprising guiding a patient-specificfemoral resection through the cutting block.
 16. The method of claim 2,further comprising mating a portion of the inner surface of the femoralalignment guide to at least one of articular cartilage and underlyingbone of the femoral joint surface.
 17. A method of preparing a kneejoint for a prosthesis in a patient, the method comprising: mating apatient-specific three-dimensional curved inner surface of a tibialalignment guide onto a corresponding three-dimensional tibial jointsurface of the patient, the patient-specific three-dimensional curvedinner surface preoperatively configured from medical scans of the kneejoint of the patient; and wrapping a portion of the tibial alignmentguide around an anterior-medial edge of the tibial joint surface. 18.The method of claim 17, further comprising: drilling a first tibialguiding hole into an anterior portion of the tibial joint surfacethrough a first corresponding anterior aperture of the tibial alignmentguide.
 19. The method of claim 18, further comprising drilling a secondtibial guiding hole into an anterior portion of the tibial joint surfacethrough a second corresponding anterior aperture of the tibial alignmentguide.
 20. The method of claim 19, further comprising inserting firstand second guiding pins through the corresponding first and secondanterior apertures and into the corresponding first and second tibialguiding holes.
 21. The method of claim 20, further comprising removingthe tibial alignment guide without removing the first and second guidingpins by sliding the tibial alignment guide through open portions ofcorresponding perimeters of the first and second anterior apertures ofthe tibial alignment guide.